Using iMac 21.5inch Mid-2011 with MacOS High Sierra as a Target Display

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Using iMac 21.5inch Mid-2011 with MacOS High Sierra as a Target Display

Has anyone done this https://support.apple.com/en-us/HT204592 successfully from a 2020 MacBook air that has a Thunderbolt 3 output (I'm using a brand new apple adapter and thunderbolt 2 cable)? Everything I read says this should work but I'm having no luck.

MacBook

Posted on Apr 24, 2020 4:10 PM

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Answer 1

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BDAqua

Level 10

245,579 points

Apr 26, 2020 10:59 AM in response to JaBluestar

Sorry, I'm as mystified as you...

You can connect any of these older iMac models to another Mac from 2019 or earlier for use as an external display. Learn how to identify your iMac model.

27-inch iMac models introduced in 2009 and 2010: Use a Mini DisplayPort cable to connect your iMac to a Mini DisplayPort or Thunderbolt or Thunderbolt 2 port on the other Mac.
All iMac models introduced in 2011, 2012, 2013, and mid 2014: Use a Thunderbolt cable to connect your iMac to a Thunderbolt or Thunderbolt 2 port on the other Mac. If the other Mac uses Thunderbolt 3, you can use the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter with your cable.

Target display mode requires macOS High Sierra or earlier on the iMac used as the external display. It does not work with macOS Mojave or later.